The study of biomaterials as implants have rapidly increased over recent decades to address the issues of tissue and bone disease. The combination of graphene oxide (GO) with hydroxyapatite (HA) is expected to promote the adsorption of protein fibronectin (FN). GO was produced by Hummer’s method. Calcium hydroxide (Ca(OH)2 at 0.1, 1.0 and 2.0 M) was used as a precursor of HA for the synthesis different GO compositions (0%, 0.1% and 1.0%) through wet chemical precipitation method. The molarity of Ca(OH)2 and the composition of GO played an important role in the morphology, particle size, distribution of GO on HA surface and absorption of protein. GO and GO-HA composites were characterized using Fourier transform infrared spectroscopy, X-ray diffraction and field-emission scanning electron microscopy. Energy-dispersive X-ray spectroscopy was used to investigate protein adsorption. The average percentage yield of GO-HA composite production was highest (96.93%) at 2.0 M of Ca(OH)2. The optimum condition of GO–HA composite was 0.1 M Ca(OH)2 and 0.1% GO composition, which resulted in needle-like shape with 48.38 nm width and 201.0 nm length, well conjugation, as well as the higher distribution of GO onto the HA surface. The elemental composition of carbon (C) of GO-HA was 44% and that of uncoated HA was 33%, which confirmed the adsorption of FN. Moreover, carbon element mapping proved that the absorption of FN towards GO-HA was successful. GO-HA nanocomposite can be a promising highly biocompatible material for medical implants.